import java.io.IOException;
import java.sql.*;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) throws Exception {
        m1();
        m2();
        m3();
    }

    private static void m3 () throws Exception{
        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection conn=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8","root","123456");
        String sql="insert into sys_user values(?,?,?)";
        PreparedStatement ps=conn.prepareStatement(sql);
        ps.setString(1,"3");
        ps.setString(2,"admin");
        ps.setString(3,"admin");
        int i = ps.executeUpdate();
        ps.close();
        conn.close();
    }

    private static void m1() throws Exception {
        Connection conn=null;
        PreparedStatement preparedStatement=null;
        ResultSet resultSet=null;
        try{
            //1.加载驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.获取连接
            conn=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8", "root", "123456");
            //3.编写sql语句
            String sql="select * from sys_user";
            //4.预处理sql var.
            preparedStatement = conn.prepareStatement(sql);
            //5.如果有参数，设置参数
            //6.执行sql
            resultSet = preparedStatement.executeQuery();
            //7.如果是查询就遍历结果，如果是增删改查 判断是否成功
            while (resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println("id:"+id+",name:"+name+",pass:"+pass);
            }
        }
        catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
        catch (SQLException e) {
            throw new RuntimeException(e);
        }
        finally {
            //8.关闭资源
            try{
                if(preparedStatement!=null)
                    preparedStatement.close();
                if (resultSet!=null)
                    resultSet.close();
                if (conn!=null)
                    conn.close();
            }
            catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }

    private static void m2() throws Exception{
        Connection conn=null;
        PreparedStatement preparedStatement=null;
        ResultSet resultSet =null;
        try {
            Scanner sc = new Scanner(System.in);
            System.out.println("请输入您要输入的字符");
            String word = sc.next();
            //1.加载驱动
            Class.forName("com.mysql.cj.jdbc.Driver");
            //2.获取连接
            conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8", "root", "123456");
            //3.编写sql语句
            String sql = "select * from sys_user where name like ?";
            //4.预处理sql var.
            preparedStatement = conn.prepareStatement(sql);
            //5.如果有参数，设置参数
            preparedStatement.setString(1, "zhangsan");
            //6.执行sql
            resultSet = preparedStatement.executeQuery();
            //7.如果是查询就遍历结果，如果是增删改查 判断是否成功
            while (resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println("id:" + id + ",name:" + name + ",pass:" + pass);
            }
        }
        catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        }
        catch (SQLException e) {
            throw new RuntimeException(e);
        }
        finally {
            //8.关闭资源
            try{
                //NullPOintException
                if(resultSet!=null)
                    resultSet.close();
                if(preparedStatement!=null)
                    preparedStatement.close();
                if(conn!=null)
                    conn.close();
            }
            catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
}